Closed circuit. Ball bearing. Body part, passive/inactive like a sandbag not a basketball. Being charged.
Six sealing and four closing can explain everything. Training model (small element): kua drives the arm. Lock the shape of the arm, arm parallel to the floow, use kua to propel the elbow transferring to the hand. Push into the front foot or back foot, the arm is positive circle or negative circle. Hand elbow shoulder is on a table, no turning of the hand. Arm is like the bifolding door. Clear one on one transmission. Kua pumps upward to the shoulder, shoulder stays down, it goes to the elbow. T, vertical to horizontal. By passing the shoulder, kua is connected directly to the elbow then to the hand. Elbow is a dot. Hong chopped his shoulders off. Upper dantian needs be clear and light. Like a bridge, from a square, chop the corners off, form an arc. Transfer of energy, cannot get stuck on the shoulders. When done right, you are always with the flow and the opponent is always against the flow.
In Taiji, we are creating function of sphere using a non-spheric shape of the body. Two ropes intertwining forming double helix. Traditional training vs modern training. MT-you learn the theory and do sth makes the body feel good. TT-your life depends on it. Total change of the body.
Superficial vs fundamental. “My movement does not have movement.” The tank tread, looks like doing smooth circles, but it is small square pieces handing 45 degree. The circle in PM is completed by 9 pieces of different edged parts, creating an illusionary smoothness.
In PM, there is a lot of corners you never used. That is why without training, no matter what background you are from, you feel your body is stiff. Kua is open, dantian becomes larger, containing all the movements. Internal strength without physical movements, compressed spring, always loaded.